Lake St. Clair Fishing Forum banner
1 - 11 of 11 Posts

·
Registered
Joined
·
2,576 Posts
Well, I have a good topic here I think.
There is a no good way really to start a cold boat or boat period.

So My Merc runs like a top. Tap on wood. I service the hell out of it and everything is good. My 4bb Carb is original and last time it was rebuilt was like 4 years ago. I found a tag on it.
When my boat is hot or been running it starts like a champ half a click.
If I let it sit for 2 days it takes about 4 cranks with throttle half way up.

Now last year I am at South River Rd. It was like 47 or even colder in the morning. I dump the boat. Pumped the throttle 3 times and put it half way up. I crancked and crancked and nothing. You get that feeling like everyone is watching you at that point. Well my choke was closed and was working fine. I ended up starting the boat at full throttle after about 30 min of crancking.
After that i never had problems but yet I put the boat away for the winter. Summer time it start on 2nd try most of the time.
Also if I engine is hot and I am fishing with engine ON sometimes it wont idle when lake is rough?

So what procedure you guys take during a cold start or any start on your Carbed Merc.NOT HOT

I will also be installing a fuel water separator on my boat this spring. and all new fuel filters.
NOTE: My carb has the spring type choke. When hot it releases and opens up. Should I buy updated style Carb with electric choke?
 

·
Registered
Joined
·
22,943 Posts
There is a bit of a learning curve for each boat/engine, and a bit of judgement needed at each startup. A cold start is different from a warm start, etc.

Starting mine cold, it takes probably 6 or 8 pumps of the throttle, which causes the accelerator pump squirt fuel with each application of the throttle.

Chokes can be a pain, but basically, as soon as you move a cold engine throttle off idle, the choke should close. Ideally, you should be able to start cranking, and then maybe apply a pump or two of throttle while cranking, as needed, until the engine fires up.

If anything, its better to error lean than rich. You can always add/pump more, but it's impossible take it back.

If it will only start in WOT, that is a sign of too much fuel, and possibly flooded.

Personally, I kind of like all this, because it takes a little effort to bring her to life. To make up for this loss of interaction on our newer boat, I like to start both engines at the same time. Either way, the boat engines firing up always bring a smile!
 

·
Registered
Joined
·
1,461 Posts
My engines are 37yrs old... Carter 4bbls. Warm starts are easy, just turn the key, no pump, no choke. Cold starts happen best when engines are cranked a bit w/o touching throttles to ensure gas in carb and @ pressure... then push throttles all the way to WOT 2 times and pull back to just above idle position. Hit key again and they'll almost always start on first try.
 

·
Registered
Joined
·
10,183 Posts
I have Crusaders, but all carb engines should really operate similarly... if adjusted right.

On mine, I pump the throttles twice about 1/2 way up, then crank. After they start I have to apply a little throttle to keep the idle around 800 until they get a little warm (1min or so). I should really NOT have to do this, as the choke should kick the throttle to the right setting, but I never messed with it to get it right when I rebuilt the carbs years ago.

If it takes more than two pumps of the throttle, you're probably draining or evaporating fuel out of the bowls. If you have to leave the throttles up at 1/2 or more then you are running way too rich and do risk flooding. It also contaminates the oil with raw gas every time you do that.

It is good for your engine to crank a few revs before it starts, so it can pre-pressure the oil galleries and get some oil in the bearings before those pistons start firing away - I'm kinda likin' Capt Ken's "crank first then do the throttle pump" move.

Spring-type chokes should work just fine. They can have problems if mis-adjusted or if the bimetal spring is bad. They should be fully open when warm and SNAP shut when you first apply throttle after the engines have cooled entirely down. You also have to make sure the "choke pull-off" mechanism works correctly. This insures the choke opens JUST ENOUGH after the engine starts to let enough air in to run the engine when cold and the choke spring is trying to keep it closed.
 

·
Registered
Joined
·
2,576 Posts
Discussion Starter · #5 ·
I think my carb is due for a rebuild. I might do it after this season. I really want to upgrade to a elctric choke carb which is only 280.00. All I have to do is run a + wire to the engine compartment which has like 1000 of them anyway and get rid of my spring loaded one. I priced it out its cheaper to buy a new carb then have it rebuild by someone or order the rebuild kit which is only 100 bucks less. Then you have to count all tools needed to do the job right.
 

·
Registered
Joined
·
10,183 Posts
QUOTE(Big_Z @ Mar 11 2010, 10:00 AM) <{POST_SNAPBACK}>I think my carb is due for a rebuild. I might do it after this season. I really want to upgrade to a elctric choke carb which is only 280.00. All I have to do is run a + wire to the engine compartment which has like 1000 of them anyway and get rid of my spring loaded one. I priced it out its cheaper to buy a new carb then have it rebuild by someone or order the rebuild kit which is only 100 bucks less. Then you have to count all tools needed to do the job right.

Just be SURE it's a "marine-rated" carb if you replace it. If it has been rebuilt before or has some wear, you may have more to do than just a rebuild kit. Older carbs might need the throttle shafts removed and new bushings put in to take up any 'slop' which causes vacuum leaks. Nothing wrong with going to an electric choke, in fact they are easier to adjust when you need to.

If it's only $280 for the whole thing, you might want to do it earlier in the season... if you're old one is running too rich you could save yourself almost that much in gas!
 

·
Registered
Joined
·
702 Posts
QUOTE(KMC @ Mar 12 2010, 09:08 PM) <{POST_SNAPBACK}>QUOTE(Big_Z @ Mar 11 2010, 10:00 AM) <{POST_SNAPBACK}>I think my carb is due for a rebuild. I might do it after this season. I really want to upgrade to a elctric choke carb which is only 280.00. All I have to do is run a + wire to the engine compartment which has like 1000 of them anyway and get rid of my spring loaded one. I priced it out its cheaper to buy a new carb then have it rebuild by someone or order the rebuild kit which is only 100 bucks less. Then you have to count all tools needed to do the job right.

Just be SURE it's a "marine-rated" carb if you replace it. If it has been rebuilt before or has some wear, you may have more to do than just a rebuild kit. Older carbs might need the throttle shafts removed and new bushings put in to take up any 'slop' which causes vacuum leaks. Nothing wrong with going to an electric choke, in fact they are easier to adjust when you need to.

If it's only $280 for the whole thing, you might want to do it earlier in the season... if you're old one is running too rich you could save yourself almost that much in gas!



I agree, Make sure it is a marine carb. If it is a marine 4bbl for $280 let us know where you are getting them. That is about 1/2 of what usually see them for. West is closer to $500 for a 2bbl and $850 for a 4bbl. Just remember if it says marine or aircraft quadruple the cost!
 

·
Registered
Joined
·
4 Posts
Just a reminder. The 12 volt power needs to run through an oil pressure switch. This ensures that choke opening (warming) follows engine warm-up. If engine stalls it kills power to choke so you not left with warm choke and cold engine. T off oil pressure sending unit. hope this helps
 

·
Registered
Joined
·
22,943 Posts
QUOTE(racecarfan @ Mar 19 2010, 08:57 AM) <{POST_SNAPBACK}>
Just a reminder. The 12 volt power needs to run through an oil pressure switch. This ensures that choke opening (warming) follows engine warm-up. If engine stalls it kills power to choke so you not left with warm choke and cold engine. T off oil pressure sending unit. hope this helps
Good point! And...

Welcome to LSCN!
 

·
Registered
Joined
·
3,013 Posts
A lot depends on the manufacturer of the carb. My boat has twin 454 Magnums with Quadrajets; both have been rebuilt. I have to crank them for 15-20 seconds before the engines will fire. Usually stalls once or twice then runs fine.

I have basically the same engine in my 'vette but I dumped the Q-jet and replaced it with a Holley. That thing fires and starts with minimal cranking and never stalls. Case in point - fired it up this week after being in storage since last November. Cranked maybe 5 seconds, let her idle for about 10 seconds, put it in gear and drove to work.

Wish I could afford two more Holleys for the boat !!!
 
1 - 11 of 11 Posts
Top